Dust Collection and Valves Blog

When designing a dust collection system, the static pressure required of the system is extremely important. The reason is because the exhaust fan must be able to pull the design airflow at the design static pressure in order to get the design performance. Usually the higher the static pressure is the greater power is required by the fan at a constant airflow. This means, dust collector system designers usually try to keep the total static pressure low, in order to go with a smaller fan that costs less to operate.

Cyclones Pressure Drop

However, when it comes to cyclones, this is not always the best policy. A cyclones pressure drop is based on the amount of air going through it. So a 24” diameter cyclone might have a 3” pressure drop at 1500 CFM and a 5.5” pressure drop at 2000 CFM. So a smaller cyclone can handle a higher airflow at a higher pressure drop. This would lower the fabrication cost of the cyclone, and allow it to fit in a more confine space, but have a higher operational cost (more HP required).

Higher Pressure Drop

But using a smaller cyclone also has another benefit, the higher your pressure drop, the more efficient the cyclone will be. This increase in removal efficiency usually will not allow you to use a cyclone only for dust control, but it will help remove smaller particulate before your primary filter. This will allow you to capture more material before contamination, lower the loading on your filters, and decrease utility usage (water or plant air).

So when you are designing a dust collection system, don’t look for the cyclone with the lowest pressure drop, but look at all the aspects that affect the system. Will a smaller cyclone fit better? Will higher removal efficiency in the cyclone be beneficial to the main dust collector?

How the Aerodyne SplitStream Cyclone Works

The SplitStream Cyclone Collector is designed for dust collection systems where tough dust like abrasive, sticky, fibrous, hygroscopic or granular persist. Configured horizontally or vertically, the cyclone’s low-profile design is perfect for mounting in space-restricted areas.

5 Signs Your Dust Collection System Needs Maintenance

Is your dust collection system working at peak efficiency? A quick, do-it-yourself examination may identify symptoms that your system needs a check-up.

To learn more about which dust collector, please contact our experts at 440-543-7400 or visit our website: www.dustcollectorhq.com

Cyclone maintenance can often be difficult. Traditional vertical cyclones are tall with long sloping hoppers making access for maintenance limited. Additionally, confined workspace can require special hardware to clean. Smaller versions can be disassembled but may require the unit to be disconnected from the airlock and duct work for cleaning procedures.

OSHA Special Procedures Requirement

OSHA requires companies to have special procedures for “confined space entry”. Equipment that is large enough for an employee to enter fully and is not designed for continuous occupancy and has limited or restricted means of entry or exit is considered confined space. If a person has to go inside, they often require a “permit to enter”. This could include having a dedicated person outside. While if the worker only needs to reach inside, the requirements may not require as stringent precaution or possibly even a permit.

Horizontal Cyclones – Removable Backplate

However, horizontal cyclones (as manufactured by Aerodyne Environmental) have a removable backplate. This allows access to the cyclone internals without disassembly and disconnecting of the cyclone. Small and medium size units also allow access without having to fully go inside the cyclone. Many units are small enough that normal humans can’t even fully enter. So full confined space entry procedure may not be required. The company’s confined space entry policy should be review to see what is required.

GPC Dust Collector Spec Request

The GPC Dust Collector is an efficient way to handle your dust collecting needs.

Dust Collection Deathmatch: Baghouse vs. Cartridge

Trying to decide whether to use a cartridge collector or baghouse in your dust collection system? Find out the four factors that separate the baghouses and dust cartridges.

To learn more about which dust collector, please contact our experts at 440-543-7400 or visit our website: www.dustcollectorhq.com

A standard collector uses round or square flanged airlocks instead of a rectangular design better suited where bridging persists.These designs are great for standard dust that doesn’t bridge. They are easy to fabricate, thereby keeping cost low. However, the uniform dimensions of the flange allow the dust to be equally supported on all sides, creating a more stable environment for a dust bridge to form. One way to counteract this is by over-sizing your airlock. An example would be using a 12” rotary valve instead of an 8” valves. While oversizing the airlock lowers the chance of bridge forming. A bridge can still form due to shape of the flange.

Better Airlocks: Rectangular Rotary Valve

A better way would be to use a rectangular rotary valve. Since the rotary valve has a rectangular flange, dust trying to bridge over the opening isn’t equally supported. And any bridge trying to form across the long axis will be unstable and begin to bow down into the valve opening, where the rotors will grab them and destroy the bridge, allowing the free flow of dust out of the hopper.

Do the rotary valves under your dust collectors cause maintenance headaches? Are they clogging? Are you having to drop everything and assign extra labor to fix them?

The disadvantages of Rotary Valve

Most dust collectors are equipped with a motor-driven rotary airlock valve that empties contents from the hoppers. Rotary valves have been used for many years and are probably the most widely used airlock design. However, maintaining rotary valves is difficult and time consuming. These valves run continuously, regardless if dust is present, which leads to wasted electricity. In addition, the valves can wear out rapidly, resulting in costly repairs and replacements.

Best Alternative: Aerodyne Vacu-Valve ®

A highly cost-effective alternative is Aerodyne’s Vacu-Valve ® Trickle Valve System. The Vacu-Valve relies on the negative pressure of the material handling system to hold the duckbill sleeve closed. As the dust or material builds up, the sleeve is forced open, allowing the contents to discharge. Once emptied, the negative pressure then immediately closes the duckbill again. This trickle valve system requires no lubrication, power, or controls. Materials that would normally jam or wear out a rotary airlock valve, the Vacu-Valve handles with ease. There is a variety of duckbill sleeve options designed for specific applications; and the Aerodyne Vacu-Valve ® is available in an open or closed design, to further accommodate the particular application.

Aerodyne’s Vacu-Valve ® is the solution! Have a look at this infographic and to learn how the Vacu-valve solves these issues and improves the discharge efficiency of your baghouse, filters and cyclones.

How Do Vacu-Valve Dust Valves Work?

To learn more about which dust collector, please contact our experts at 440-543-7400 or visit our website: www.dustcollectorhq.com.

To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

We all know that getting the oil change in our car regularly is important to the car being able to get you around when you need it. However, your dust collector needs regular maintenance too. The dust collector system consists of hoods, ductwork, air-material separators (cyclones, baghouse, cartridge collectors, wet scrubbers, etc.), explosion protection equipment, airlocks, instrumentation, and exhaust fans.

All of these items should be checked at least once a year to make sure they are operating correctly. The following points briefly describe what each piece of equipment needs:

1. Hoods

Visual inspection to make sure they haven’t been damaged during the year.

Measure airflow velocity to make sure they are collecting the design airflow.

If a local damper is located by hood for balancing, make sure it is operable and in the correct position.

2. Ductwork

Visual inspection to make sure no holes have developed.

Measure air velocity through ductwork to make sure designed airflow is correct.

If possible, visual inspection of duct internal to make sure dust isn’t building up.

3. Air Material Separators

Measure pressure drop across the separator to see if it is within parameters.

Inspect cleaning process (baghouses and cartridge collectors) that they are operating properly (timing, valves opening, air pressure, etc.). See operations and maintenance manual. Often time, listening to the system will let you know if it is operating correctly.

Monitor recycle line pressure and overflow in wet scrubbers.

Visual inspection of vessel walls to be sure there are no holes.

4. Explosion Protection Equipment

NFPA requires yearly inspection, following the manufactures manual is very important so the explosion protection equipment will protect the facility, equipment, and workers as it was designed.

Some explosion protection equipment such as chemical suppression should be done by factory trained personnel.

Look under almost any dust collector and you will see a rotary airlock valve spinning its rotor and emptying the collected contents from the hopper. These valves have long been used to maintain a seal in vacuum dust collection systems while simultaneously providing an escape route for the dust. The advantages of a rotary airlock for dust collectors include, automatic hopper emptying, minimal vacuum pressure loss, and the many options available to meet specific application needs. Rotary valves can be custom fit to handle high temperatures, harsh chemical environments, and abrasive materials. Rotary valves do however, have a few major drawbacks.

Because rotary airlocks are sealed tight to the atmosphere they can be very difficult to clean. Cleaning a rotary valve often involves removing the drive assembly, end plate, and finally the rotor. This process can take hours to perform. Rotary valves are also expensive to operate. Typically, these valves are left running continuously, even when there is no dust present in the hopper. This not only wastes electricity but puts undo wear on the valve. Repair and replacement parts for rotary airlock valves can be quite costly as well. Even with these shortcomings, the rotary airlock remains the industry standard for most dust discharge applications.

One alternative which has been gaining popularity is a non-powered automatic dust discharge valve. These valves, like the Armadillo and Platypus Vacu-Valves from Aerodyne, rely on the negative pressure (max -18" W.C.) of a dust collector to hold a rubber sleeve closed to maintain an airlock. As the weight of the dust in the hopper builds up, the sleeve is forced open and dust is discharged from the valve. Leaf springs inserted into the valves sleeve also help to counterbalance the vacuum. Avideo demonstrationof how this works is availablehere. The valves are available with a variety of sleeve materials for different applications. While these valves can not be used in every dust collection system they are a very economical alternative to expensive rotary valves.

The Vacu-Valves from Aerodyne are priced at a fraction of the cost of standard rotary airlock valves and require no electricity to operate. These valves have no controls and require no lubrication. They easily handle abrasive materials that would jam or wear out a rotary valve.

To learn more about which dust collector valve is right for you, please contact our experts at 440-543-7400 or click on the button below to get our infographic, Vacu-Valve is a Simpler Solution.

When your dust collectors are having issues, one of the first places to look is the airlock valve. Often times, dust is hygroscopic and when outside air leaks into the system, humidity follows. This can cause the dust to absorb the humidity and become sticky or harden like cement. This can lead to plugged filters, hoppers and damage to rotary valves. While rotary valves are the industry standard airlock, they constantly allow air leakage. A low leakage valve is required. Double dump valves however are very low leakage, since there is no direct connection to the outside atmosphere. The valve always isolates the conditions above it from the conditions below it. This minimizes air leakage, thereby minimizing humidity from affecting the dust.

So if you have a non-explosive application that is hygroscopic, look into a double dump (flap) valve.

Find out more information now.

If you are having operational issues on your dust collection system, contact
Aerodyne at 440-543-7400 or
dc@dustcollectorhq.com.

In order for a dust collector to operate at its peak performance, the hopper has to be isolated from the outside. This means either the dust bin/receptacle is “hard connected”, meaning there are no air leaks or an airlock is used. An airlock isolates the dust collector hopper from the outside, while allowing the collected dust to exit the system. Common airlocks are rotary valves, trickle valves, double dump valves, and knife gates. Some airlocks are low leakage (double dump valve and trickle valves) while others have continuous leakage (rotary valves).

Airlocks are important because without them air will enter (system under vacuum) or leave (pressurized system) through the dust discharge valve. If the system is under vacuum, the air entering the system from the dust discharge will re-entrain the dust back into the clean air, thereby lowering removal efficiency. If the system is under pressure, air will blow out of the bottom, spreading dust everywhere, creating unnecessary maintenance cost for the facility.

If the system is dealing with an explosive dust, an airlock should be used to prevent an explosion from propagating from the dust discharge flange. Specially designed rotary valves are used to prevent this.

Furthermore, airlocks allow you to change the dust bin without shutting off the system. If you don’t have an airlock, when you need to change your dust bin, you either have to turn off the system, or operate the unit without any isolation.

So when you are spending money to capture your dust in a dust collector, don’t forget to put an airlock on it, so you will have the best performance possible.

Read our article on what type of airlock valves to use in particular applications.

If you are having operational issues on your dust collection system, contact Aerodyne at 440-543-7400 or dc@dustcollectorhq.com.

Aerodyne Environmental: Home of the Horizontal Cyclone and Vacu-Valve® Airlock Valve

Inspired To Be Different.

At Aerodyne, we choose to take a different approach to collecting dust and handling materials. Our cyclones are unique in design to address common issues such as problematic dusts and space constraints. Our airlocks are chosen to fit your specific application instead of hastily installing traditional equipment options. We believe that when we see things differently, we can solve problems effectively. That's why so many people turn to us for help in solving their tough dust problems.